Method and system for an integrated VSB/QAM/NTSC/OOB plug-and-play DTV receiver

ABSTRACT

Systems and methods for processing signals in a communication system are disclosed and may include demodulating a wirelessly received inband signal and a wirelessly received out-of-band signal via a DTV receiver. One or more TV channels may be generated based on the demodulation of the wirelessly received inband signal and a wirelessly received out-of-band signal. The received inband signal may include a VSB signal, a NTSC signal and/or a QAM signal. The processing may also include determining whether the wirelessly received inband signal includes an analog signal or a digital signal. The digital signal may be error corrected, and the error corrected digital signal may be equalized. The analog signal may be decoded, and an audio output may be generated based on the decoding of the analog signal.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application is a continuation of U.S. application Ser. No.10/774,037 filed Feb. 6, 2004.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to television receiversystems. More specifically, certain embodiments of the invention relateto a method and system for a vestigial side band (VSB), quadratureamplitude modulation (QAM), NTSC, out-of-band (OOB) receiver.

BACKGROUND OF THE INVENTION

Digital television, popularly referred to as DTV, is an enhancedtelevision system capable of transmitting and receiving digitizedsignals, displaying digital images and playing digital audio. While someof these features may be present in current analog television systemssuch as national television standards committee (NTSC), sequentialcouleur avec memoire (SECAM) and phase alternate line (PAL), thecombination of digitized transmission, reception, video and audiodistinguishes digital television from current analog television systems.

Digital television employs various digital signal processing techniquesand utilizes scarce bandwidth in a more spectrally efficient manner totransport and present audio and video signals in a way that is superiorto current analog television systems. In this regard, digital televisionallows more channels containing more information to be broadcastedwithin an equivalent bandwidth utilized by current analog televisionsystems. Accordingly, any excess bandwidth can be re-allocated for useby other types of communication systems. Broadcasters utilizing digitaltelevision systems are therefore, capable of providing over-the-airtelevision signals containing higher picture resolutions than currentanalog broadcast television systems. Broadcasters utilizing digitaltelevision systems may also have the capability to provide multicastingand datacasting services using the same bandwidth allocated forconventional analog television systems. For these reasons, Congressmandated that current broadcast television service must, in time, becompletely converted to digital television.

While digital television (DTV) utilizes the same broadcast very highfrequency (VHF) spectral band and ultra-high frequency spectral (UHF)band as conventional television broadcasting systems, digital televisionutilizes different modulation techniques than conventional analogtelevision broadcasting systems. Conventional analog televisionbroadcasting systems modulate video using amplitude modulation (AM) andthe accompanying audio is modulated using frequency modulation (FM). DTVutilizes a plurality of modulation techniques for transmitting andreceiving packetized digital signals. In the United States of America,an eight level vestigial sideband (VSB) modulation scheme is utilized.In some regions of Europe and Asia, for example, coded orthogonalfrequency division multiplexing is the modulation scheme of choice. Onthe other hand, digital satellite systems (DSS) utilize quadrature phaseshift keying, while cable television (CATV) system utilizes quadratureamplitude modulation (QAM).

In the United States, a plurality of broadcast formats promulgated bythe Advanced Television Standards Committee (ATSC) has been adopted forDTV applications. Some of these formats comprise progressive-scan videocomprising 480 scan lines referred to as 480p, interlaced 4:3 videohaving 480 scan lines referred to as 480i, interlaced video having 1080scan lines referred to as 1080i and progressive-scan video having 720scan lines referred to as 720p. Standard definition (SD) television(SDTV) utilizes the interlaced 480i and progressive 480p formats. Thepicture quality provided by SDTV is comparable in certain respects toconventional NTSC 525 lines systems. High definition (HD) television(HDTV) utilizes the interlaced 1080i and progressive 720p formats in a16:9 aspect ratio. The resolution of the HDTV interlaced 1080i andprogressive 720p formats may be converted to lower resolution such asthe interlaced 480i and progressive 480p formats provided by SDTV.

In the US for example, DTV signals are modulated on an RF carrier using8-level VSB or 8VSB, and transmitted in a six (6) MHz channel ascompressed 4:2:0 MPEG-2 formatted packetized streams. These packetizedstreams contain both audio and video information. For this reason, aconventional analog system is unable to receive a transmitted DTVsignal. In order to decode a received 8-level VSB signal, anATSC-compliant DTV receiver or a set-top box is required.

FIG. 1 is a block diagram of a conventional digital television (DTV)receiver. Referring to FIG. 1, the receiver 100 comprises an antenna102, a tuner 104, a demodulator block 106, an equalizer 110, a phasetracking block 112, a trellis decoder 114, a de-interleaver 116, a ReedSolomon (RS) decoder 118 and a de-randomization block 120.

The antenna 102 is coupled to the tuner 104, which is adapted to receive6 MHz VHF or UHF signals. The tuner 104 includes a band pass filter thatpasses signals in the range of about 50 MHz to about 810 MHz, therebyrejecting any unwanted signals. The demodulator block 106 is adapted toreceive and process NTSC signals and may include circuitry that isutilized to mitigate the effects of co-channel interference. Theequalizer 110 is adapted to compensate for linear distortions that mayhave occurred during transmissions. The phase tracking block 112 may beutilized to track and eliminate unwanted noise. The trellis decoder 114reduces co-channel interference and impulse noise. The de-interleaver116 and the Reed Solomon (RS) decoder 118 may cleanup the signal andremove any unwanted burst interference that may affect image quality.The trellis decoder 114, de-interleaver 116 and the Reed Solomon decoder118 significantly reduces errors that may occur in the received signal.The de-randomization block 120 is configured to receive the errorcorrected signal from the Reed Solomon decoder 118 and de-randomizes theerror corrected signal using the same pseudorandom sequence utilized torandomize the original signal during transmission.

The receiver of FIG. 1 is adapted to receive and demodulate only 8-levelVSB modulated signals. In most instances, the tuner 104, filter block106, equalizer 110, phase tracking block 112, trellis decoder 114,de-interleaver 116, Reed Solomon (RS) decoder 118 and de-randomizationblock 120 are integrated into a plurality of integrated circuits (ICs)which have to be coupled together by suitable circuitry and/or logic.Accordingly, any receiver implementation utilizing these integratedcircuits would require a significant investment in scare and expensiveprinted circuit board (PCB) real estate and complex design layouts. Evenin instances where most of the components of FIG. 1 are integrated in afew integrated circuits, the resulting receiver is limited to NorthAmerican digital terrestrial broadcast television signals. Furthermore,with the promulgation of standards such as the CableCard specification,any out-of-band signal processing would require additional ICs and/orcircuitry to handle out-of-band signal processing. This would furtherrequire the use of additional PCB real estate, further increasing costand design complexity.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor processing television signals. Aspects of the method may comprisereceiving an inband signal by a single chip integrated DTV receiver anddemodulating the received signal within the single chip DTV receiver. Anout-of-band signal corresponding to the received inband signal may bereceived and processed on-chip by said single chip integrated DTVreceiver. The received inband signal may be a VSB signal, a NTSC signal,or a QAM signal, for example. If the received inband signal is a VSBsignal, the demodulated received inband signal may be error correctedwithin the single chip integrated DTV receiver to generate an errorcorrected ATSC compliant signal. If the received inband signal is a QAMsignal, the demodulated received inband signal may be error correctedwithin the single chip integrated DTV receiver to generate an errorcorrected ITU-T J.83 signal which is compliant with Annex A, Annex Band/or Annex C of ITU-T J.83. If the received inband signal is a VSBsignal, the error corrected ATSC signal may be equalized within thesingle chip integrated DTV receiver. If the received inband signal is aQAM signal, the error corrected ITU-T J.83 compliant signal may beequalized within the single chip integrated DTV receiver.

An output MPEG transport stream may be generated from the demodulatedreceived inband signal within the single chip integrated DTV receiver.The MPEG transport stream may be a serial or parallel MPEG transportstream. If the received inband signal is an NTSC signal, the demodulatedreceived inband signal may be decoded within the single chip integratedDTV receiver. An I²S audio output, a stereo audio output, a monauralaudio output, and/or a multiplexed baseband audio output may begenerated from the decoded demodulated received inband signal fromwithin the single chip integrated DTV receiver. If the received signalis an NTSC signal, a composite NTSC signal may be generated from thedemodulated received inband signal within the single chip integrated DTVreceiver. The received out-of-band signal may be demodulated within thesingle chip integrated DTV receiver using for example, a QPSKdemodulator. The demodulated received out-of-band signal may also beerror corrected within the single chip integrated DTV receiver. Anoutput out-of-band transport stream may be generated from the processedreceived out-of-band signal from within the single chip integrated DTVreceiver. The out-of-band transport stream comprises CableCardencryption and security data. Demodulation of the received inband signaland/or the out-of-band received signal may be controlled via an on-chipprocessor integrated within the single chip integrated DTV receiver.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described above for processing television signals.

Aspects of the system for processing television signals may comprise aninband analog front end integrated in a single chip integrated DTVreceiver that receives an inband signal. A demodulator within the singlechip DTV receiver may demodulate the received inband signal. Anout-of-band analog front end integrated within the single chipintegrated DTV receiver may be adapted to receive an out-of-band signalcorresponding to the received signal. An out-of band receiver integratedwithin the single chip integrated DTV receiver may process the receivedout-of-band signal. The received inband signal may be a VSB signal, aNTSC signal, or a QAM signal, for example.

An ATSC FEC may be utilized to error correct the demodulated receivedinband signal within the single chip integrated DTV receiver andconsequently generate an error corrected ATSC compliant signal, if thereceived inband signal is a VSB signal. An ITU-T J.83 compliant FEC maybe utilized to error correct the demodulated received inband signalwithin the single chip integrated DTV receiver and consequently generatean error corrected ITU-T J.83 compliant signal if the received inbandsignal is a QAM signal. The ITU-T J.83 compliant signal may be compliantwith Annex A, Annex B and/or Annex C of ITU-T J.83 specification. Atleast one equalizer may equalize the error corrected ATSC signal withinthe single chip integrated DTV receiver if the received inband signal isa VSB signal. The equalizer may be utilized to equalize the errorcorrected ITU-T J.83 compliant signal within the single chip integratedDTV receiver if the received inband signal is a QAM signal.

The system may further comprise an inband output interface thatgenerates from within the single chip integrated DTV receiver, an outputMPEG transport stream from the demodulated received inband signal. Theoutput MPEG transport stream may be a serial or parallel MPEG transportstream. A BTSC decoder may decode the demodulated received signal withinthe single chip integrated DTV receiver if the received inband signal isan NTSC signal. A least one of the BTSC decoder and an audio DAC maygenerate from within the single chip integrated DTV receiver, an I²Saudio output, a stereo audio output, a monaural audio output, and/or amultiplexed baseband audio output from the decoded demodulated receivedinband signal. A DAC may generate a composite NTSC signal from thedemodulated received inband signal within the single chip integrated DTVreceiver if the received inband signal is an NTSC signal.

A demodulator, for example, a QPSK demodulator may be utilized todemodulate the received out-of-band signal within the single chipintegrated DTV receiver. A DVS-167 compliant FEC and/or a DVS-178compliant FEC may error correct the demodulated received out-of-bandsignal within the single chip integrated DTV receiver. An out-of-bandoutput interface may generate an output out-of-band transport streamfrom the processed received out-of-band signal from within the singlechip integrated DTV receiver. The out-of-band transport stream maycomprise CableCard encryption and security data. An on-chip processormay control demodulating of the received inband signal and/or thereceived out-of band signal within the single chip integrated DTVreceiver

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional digital television (DTV)receiver.

FIG. 2 a is a function block diagram of a single chip integrated DTVreceiver in accordance with an embodiment of the invention.

FIG. 2 b is a block diagram of the inband analog front end block 204 ofFIG. 2 a in accordance with an embodiment of the invention.

FIG. 2 c is a block diagram of the 8/16 VSB advanced receiver block 206of FIG. 2 a in accordance with an embodiment of the invention.

FIG. 2 d is a block diagram of the QAM advanced receiver block 208 ofFIG. 2 a in accordance with an embodiment of the invention.

FIG. 2 e is a functional block diagram of the NTSC IF demodulator block210 of FIG. 2 in accordance with an embodiment of the invention.

FIG. 3 is a block diagram illustrating the out-of-band (OOB) QPSKreceiver for CableCard interface block 226 of FIG. 2 a in accordancewith an embodiment of the invention.

FIG. 4 is a flow chart illustrating exemplary steps that may be utilizedby a master state machine for the EIA/CEA-909 compliant interface block232 in accordance with an embodiment of the invention.

FIG. 5 a is a flow chart illustrating exemplary steps that may beutilized for accessing the HAB by a host processor in accordance with anembodiment of the invention.

FIG. 5 b is a flow chart illustrating exemplary steps that may beutilized for accessing and processing requests in the HAB 238 by anacquisition processor in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor a vestigial side band (VSB), quadrature amplitude modulation (QAM),NTSC, out-of-band (OOB) receiver which is integrated in a single chip.For brevity, the single chip vestigial side band (VSB), quadratureamplitude modulation (QAM), NTSC, out-of-band (OOB) receiver may bereferred to as a single chip integrated DTV receiver. In one aspect ofthe invention, the single chip integrated DTV receiver provides plug andplay DTV receiver capability for handling both North American digitalcable television and digital terrestrial broadcast television compatiblesystems. Accordingly, the single chip integrated DTV receiver is capableof receiving all standard-definition and high-definition digital formats(SDTV/HDTV). Furthermore, integrated within the single chip integratedDTV receiver is an NTSC demodulator compatible with the NTSC videostandard. An output of the NTSC demodulator may be directed to anexternal broadcast television system committee (BTSC) or Zweiton Mdecoder, or it may be sent to an on-chip audio decoder. The on-chipaudio decoder may be fully compliant with the BTSC audio standard. Thesingle chip integrated DTV receiver may also comprise an integratedout-of-band QPSK receiver, which may be adapted to, for example, handlea CableCard compliant with the CableCard Specification.

A CableCard, commonly referred to as point-of-deployment (POD) removablesecurity module, is a module that may be utilized to enable portability.In this regard, the CableCard ports certain features and functionalitiesof a set-top box including encryption, security, and other privatenetwork features, onto a removable device or media. The removable deviceor media may be similar in size to, for example, a personal computermemory card international association (PCMCIA) card. The CableCard maybe inserted or plugged into a host device such as a set-top box or DTVreceiver, and may provide conditional access (CA) functionality. Theconditional access functionality may be utilized to decrypt encrypteddigital content received by the host system such as the DTV receiver.The CableCard permits an owner of a receiver to move from a firstservice provider to a second service provider without having to purchasea new receiver for use with the second service provider. In this regard,when the owner of the receiver switches service to the second serviceprovider, only the CableCard needs to be replaced or updated withrelevant information for the second service provider.

A QAM demodulator and a VSB demodulator integrated within the singlechip integrated DTV receiver may be referred to as an integrated digitalreceiver. An analog front end (AFE) integrated within the single chipintegrated DTV receiver may be adapted to receive an analog signalcentered at the standard television image (IF) frequencies. The analogfront end may be adapted to amplify and digitize the received analogsignals using an integrated programmable gain amplifier and an A/Dconverter. The output of the A/D converter may be transferred to theintegrated DTV receiver, which comprises the QAM demodulator and the VSBdemodulator. Each of the QAM demodulator and VSB demodulator maycomprise one or more adaptive filters which are configured to remove orotherwise mitigate the effects of multi-path propagation, NTSCco-channel interference and RFI interference.

The output of the VSB demodulator may be transferred to an ATSC A/53coding forward error corrector (FEC), with integrated trellis and ReedSolomon decoder. The output of the QAM demodulator may be transferred toan ITU-T J.83 Annex A/B/C coding forward error corrector (FEC). Theoutputs from the ATSC A/53 coding forward error corrector and the ITU-TJ.83 Annex A/B/C coding forward error corrector may be transferred ineither a parallel or serial MPEG-2 transport format. The NTSCdemodulator may be adapted to filter and demodulate the analog NTSC andFM audio signals and delivers a composite output via an on-chip DAC.

An IF modulated audio output may also be provided via a second on-chipDAC. An on-chip or integrated BTSC decoder may be configured to handlethe decoding of baseband multiplexed audio from the NTSC demodulatorproviding, for example, a stereo Left/Right (L/R), monaural, or separateaudio programming (SAP) output via a pair of high precision audio DACs.The gain, clock, carrier, acquisition and tracking loops may beintegrated on-chip since the necessary phase-locked loops (PLLs) may bereferenced to a single external crystal coupled to an on-chip masterphase lock loop (PLL). Chip configuration, channel acquisition andperformance monitoring functions may be handled by an on-chipacquisition processor using various software code or applications.

FIG. 2 a is a function block diagram of a single chip integrated DTVreceiver in accordance with an embodiment of the invention. Referring toFIG. 2 a, the single chip integrated DTV receiver 202 may comprise aninband analog front end (AFE) block 204, an ATSC 8/16 VSB advancedreceiver block 206, a QAM advanced receiver block 208, a NTSC IFdemodulator block 210, an ATSC forward error correction (FEC) block 212,an ITU-T J.83 annex A/B/C compliant forward error correction (FEC) block214, an inband output interface block 216, D/A converter blocks 218 and220, a BTSC decoder block 222, and an audio DAC block 224. Alsoillustrated in FIG. 2 a is an out-of-band (OOB) QPSK receiver forCableCard interface block 226, a BSC master interface block 228, ageneral purpose input/output (GPIO)/general purpose output (GPO)interface block 230, an EIA/CEA-909 compliant interface block 232, and adebug interface block 234. The single chip integrated DTV receiver 202illustrated in FIG. 2 a may also comprise a BSC/SPI slave interfaceblock 236, a host access buffer (HAB) block 238, an acquisitionprocessor 240 block, and a master PLL block 242.

FIG. 2 b is a block diagram of the inband analog front end block 204 ofFIG. 2 a in accordance with an embodiment of the invention. Referring toFIG. 2 b, the inband analog front end block 250 may comprise aprogrammable gain amplifier (PGA) block 252, an automatic gain controlblock (AGC) 254 and an analog-to-digital (ND) converter 256. Theautomatic gain control block 254 may comprise a digital AGC circuitwhich may be adapted to control or adjust various power levels seen bythe QAM receiver 208, VSB receiver 206 and NTSC demodulator 210 allshown in FIG. 2 a. Adjustment of these voltage levels may be utilized toremove or otherwise mitigate the effects of any amplitude variation inthe signals entering the single chip integrated DTV receiver. Adjustmentof these voltage levels may also provide an optimal loading of the NDconverters in the inband analog front end block 250.

The sigma-delta DACs are adapted to provide a fairly simple mechanism totransfer a digital value into the analog domain. The output of the DACis a pulse code modulated (PCM) representation of a control word whichmay be provided as an input to the sigma-delta DACs. An external lowpass filter or integrator coupled to an output of a DAC may be utilizedto integrate the output of the DAC in order to remove unwanted highfrequency components. Accordingly, the analog voltage resulting from thelow pass filter and/or integrator may be proportional to the two'scomplement control word.

The inband analog front end (AFE) block 250 may be configured to receiveanalog signals at the common IF center frequencies. The internalprogrammable gain amplifier 252 provides gain to adjust the incomingsignal level. The gain based on a closed loop automatic gain control.

The 8/16 VSB receiver block 206, the QAM advanced receiver bock 208, andthe NTSC IF demodulator block 210 along with its associated BTSC decoderblock 222 may be referred to as an inband receiver. In accordance withan embodiment of the invention, a single A/D converter output from theinband analog front end block may feed each of the three receiverscomprising the inband receiver. Accordingly, only one of the threereceivers comprising the inband receiver may be operational at any giventime.

The ATSC A/53 Digital Television Standard was developed by the DigitalHDTV Grand Alliance of vendors and is the accepted standard for theterrestrial transmission of SDTV and HDTV signals in the United States.The ATSC A/53 Digital Television Standard is based on an 8-levelvestigial sideband (8-VSB) trellis coded modulation format with anominal payload data rate of about 19.4 Mbps in a 6 MHz channel. A highdata rate mode for use in a cable television environment is alsospecified by the standard, which utilizes 16-VSB to provide a payloaddata rate of 38.8 Mbps in a 6 MHz channel. This mode is also compliantwith Annex D of the ITU-T J.83 specifications. The ATSC 8/16 VSBadvanced receiver 206 in the single chip integrated DTV receiver 202 iscompliant with the ATSC A/53 Digital Television Standard's normal modeand high data rate mode.

FIG. 2 c is a block diagram of the 8/16 VSB advanced receiver block 206of FIG. 2 a in accordance with an embodiment of the invention. Referringto FIG. 2 c, the 8/16 VSB advanced receiver block 260 may comprise aphase recovery block 262, a timing recovery block 264, anacquisition/tracking loops and clock generation block 266, and outputprocessing block 268. The output processing block 268 may comprise afeed forward equalizer (FFE) block 268 a, a decision feedback equalizer(DFE) 268 c and a slicer derotator block 268 b.

For carrier recovery, carrier frequency/phase recovery and trackingloops in the phase recover block 262 of the 8/16 VSB advanced receiverblock 206 may be all-digital loops that simultaneously provide a wideacquisition range and a large phase noise tracking capability. The loopsmay be configured to utilize both pilot tracking and decision directedtechniques to estimate the angle and direction for phase/frequencycompensation. The loops may be filtered by integral-plus-proportionalfilters in which the integrator and linear coefficients of the filterare programmable in order to establish loop bandwidths. The single chipintegrated DTV receiver 202 may provide loop monitoring by utilizingsuitable logic, circuitry and/or code, which may be configured to readassociated values from the integrators.

A timing recovery loop in the timing recovery block 264 of the ATSC 8/16VSB advanced receiver 206 comprises a timing error discriminant, a loopfilter, and a digital timing recovery block that controls a digitalresampler. The timing error discriminant may be adapted to output a newvalue for each symbol that is filtered by a digitalintegral-plus-proportional lowpass filter with programmablecoefficients. In one aspect of the invention, the loop integrator may beread for loop monitoring or written for direct control by theacquisition processor block 240. For an oversampled data stream, atleast a portion of the upper bits of the loop filter may be applied to adigital resampling filter that correctly reconstructs sampled data fromthe oversampled data stream.

In a terrestrial broadcast environment, radio frequency interference(RFI) and co-channel interference from an NTSC transmitter is generallya potential problem which degrades the quality of a received signal. TheATSC 8/16 VSB advanced receiver 206 comprises an adaptive filter whichis configured to mitigate the effects of co-channel interference. Inthis regard, the adaptive filter places notches in the frequencyspectrum at the locations of the detected NTSC luma, color, and audiosubcarriers. In an aspect of the invention, the adaptive filter mayplace notches in the frequency spectrum to detect and cancel narrowbandinterferers.

While square-root Nyquist filters (not shown) in the 8/16 VSB advancedreceiver 260 will assure that there is no inter-symbol interference(ISI) over a perfect channel, they cannot remove ISI due toimperfections in the channel characteristics. Accordingly, the ATSC 8/16VSB advanced receiver 260 utilizes the feed forward equalizer (FFE)block 268 a and decision feedback equalizer block 268 c to mitigateamplitude and phase distortion resulting from ISI generated byterrestrial broadcast channels with varying multipath spreads. Inaddition to adaptive equalization, the decision feedback equalizer (DFE)block 268 c may also perform phase recovery on the equalizedconstellation points by using a quadrature synthesizer and complex mixerunder the control of the carrier recovery loop to track out residualcarrier offsets and instantaneous phase offsets.

The QAM advanced receiver block 208, may be adapted to support QAMdemodulation and may accept an analog signal centered at the standardtelevision IF frequencies, and amplify and digitize this signalutilizing an integrated programmable gain amplifier and an A/Dconverter. The QAM advanced receiver block 208 demodulates, matchfilters, and then adaptively filters the signal to remove multipathpropagation effects and narrowband co-channel interference. Integratedtrellis and Reed-Solomon decoders in the QAM advanced receiver block 208are adapted to support the IUT-T J.83 Annex A/B/C coding formats forerror correction. The output data stream from the QAM advanced receiverblock 208 may be formatted and delivered in serial MPEG-2 transportformat. Clock, carrier and gain acquisition and tracking loops areintegrated on-chip as are the necessary phase-locked loops, all of whichmay be referenced to a single external crystal coupled to the master PLLblock 242.

The QAM advanced receiver block 208 may operate in any of a plurality ofstandardized modes such as the CATV ITU-T J.83 Annex A/C mode. The ITU-TJ.83 Annex A/C standard is utilized primarily outside the United Statesfor digital cable television applications. In Europe, the ITU-T J.83Annex A/C standard is known as the Digital Video Broadcast for Cable(DVB-C) standard. The Digital Audio-Visual Council (DAVIC) has adoptedthe DVB-C standard along with various extensions to support 256-QAM. TheIEEE 802.14 committee has adopted Annex A/C as one of two possiblephysical layer standards for cable modems. Notwithstanding, the QAMadvanced receiver block 208 provides support for the full standard,including up to 8 MHz channelization, as described in ITU-T J.83 Annex Aand C, as well as all DAVIC extensions.

The QAM advanced receiver block 208 may also be adapted to operate in aITU-T J.83 Annex B mode, and provides support for ITU-T J.83 Annex Bstandard, which is currently the dominant standard for digitaltelevision delivery over CATV networks in the United States. ITU-T J.83Annex B has been adopted as the physical layer standard by variousorganizations such as the Society of Cable Telecommunications Engineers(SCTE DVS-031), the Multimedia Cable Network Systems (MCNS-DOCSIS), andthe IEEE 802.14 committee.

FIG. 2 d is a block diagram of the QAM advanced receiver block 208 ofFIG. 2 a in accordance with an embodiment of the invention. Referring toFIG. 2 d, the QAM advanced receiver block 270 may comprise a phaserecovery block 272, a timing recovery block 274, an acquisition/trackingloops and clock generation block 276, and output processing block 278.The output processing block 278 may comprise a feed forward equalizer(FFE) block 278 a, a decision feedback equalizer (DFE) 278 c and aslicer derotator block 278 b.

For carrier recovery, carrier frequency/phase recovery and trackingloops in the QAM advanced receiver block 270 may be all-digital loopsthat may be adapted to simultaneously provide a wide acquisition rangeand a large phase noise tracking capability. The loops may be configuredto utilize decision directed techniques to estimate the angle anddirection for phase/frequency compensation. The loops may be filtered byintegral-plus-proportional filters in which the integrator and linearcoefficients of the filter are programmable in order to establish andmanage loop bandwidths. Data from the loop filter may be utilized tocontrol direct digital frequency synthesizers, providing both extremelyaccurate frequency generation and fine phase resolution. The QAMadvanced receiver block 270 may provide loop monitoring by utilizingsuitable logic, circuitry and/or code, which may be configured to readassociated values from the integrators.

A timing recovery loop in the timing recovery block 274 of the QAMadvanced receiver block 270 comprises a timing error discriminant, aloop filter and a digital timing recovery block that controls a digitalresampler. The timing error discriminant may be adapted to output a newvalue for each symbol that is filtered by a digitalintegral-plus-proportional lowpass filter having programmablecoefficients. In one aspect of the invention, the loop integrator may beread for loop monitoring by the acquisition processor block 240. For anoversampled data stream, data from the loop filter may be applied to adigital resampling filter that reconstructs correctly sampled data fromthe oversampled data stream.

In cable TV systems, inter-modulation products resulting from analogCATV channels may cause narrowband co-channel interference. Accordingly,the QAM advanced receiver block 270 may comprise an adaptive filter thatplaces notches in the frequency spectrum at the location of thesesub-carriers. The use of the adaptive filter mitigates the effects ofinter-modulation products.

The phase recovery block 272 in the QAM advanced receiver block 270 maybe adapted to perform phase recovery on equalized constellation pointsby utilizing, for example, a quadrature synthesizer and complex mixer. Acarrier recovery loop may be utilized to track out residual carrieroffsets and instantaneous phase offsets. The QAM advanced receiver block270 may also comprise square-root Nyquist filters (not shown) which areconfigured to mitigate some of the effects of inter-symbol interference(ISI). While the square-root Nyquist filters will ensure that there isno inter-symbol interference (ISI) over a perfect channel, they cannotremove ISI caused by imperfections in the characteristics of a channel.Accordingly, the QAM advanced receiver block 270 utilizes the feedforward equalizer block (FFE) 278 a and the decision feedback equalizer(DFE) block 278 c which is sufficient to remove the ISI generated byworst-case coaxial cable channels with varying multipath spreads. In anaspect of the invention, blind convergence algorithms may be provided tofacilitate equalizer acquisition.

The ITU-T J.83 annex A/B/C compliant forward error correction (FEC)block 214, which may also be referred to as the A/53 FEC decoder 214,comprises a trellis decoding function, a convolutional deinterleavingfunction, Reed-Solomon decoding function and derandomization function.The A/53 FEC decoder block 214 may be adapted to receive soft decisionsfrom the 8/16-VSB receiver and locate corresponding segments and fieldsynchronization signals. In the case of 8 VSB, received data may bepassed through a trellis decoder, which may be adapted to function as amaximum likelihood sequence estimator (MLSE). For both 8-VSB and 16-VSB,the data then passes through a convolutional deinterleaver and into aReed-Solomon (RS) decoder that is capable of correcting a plurality ofsymbol errors per RS block. The resulting data may then be derandomizedand transferred to the output as, for example, an MPEG-2 serial orparallel formatted data stream comprising packet sync and a data clock.The A/53 FEC decoder block 214 may also be configured to signal thepresence of an uncorrectable error by setting an enabled transport errorindicator (TEI) flag in the output MPEG-2 data stream.

The ITU-T J.83 Annex A/B/C FEC block 214 integrated in the single chipintegrated DTV receiver 202 may be coupled to an input of the outputprocessing block 278. The ITU-T J83 Annex A/B/C FEC is compatible withall common CATV standards. The ITU-T J.83 Annex A/B/C FEC block 214 maycomprise and internal memory, which may be adapted to support commonlyutilized interleaver depths characteristic of cable systems.

ITU-T J83 Annex B decoder support may be provided through a concatenatedcoding scheme comprising trellis decoding, derandomization,convolutional deinterleaving, Reed-Solomon (RS) decoding, and checksumdecoding. This concatenated coding scheme along with interleavingprovides superior coding gain to combat gaussian noise while stilloffering good protection against burst errors. An ITU-T J83 Annex Bcompliant decoder may be integrated in the ITU-T J.83 Annex A/B/C FECblock 214. A trellis decoder may be provided and is configured tofunction as a maximum likelihood sequence estimator (MLSE) by receivingand processing soft decisions from the equalizer block 278 a and/or 278c. Resulting output sequences from the trellis decoder may betransferred to a frame synchronization block and a derandomization blockfor processing. Output data from the synchronization block may betransferred to a Reed-Solomon decoder which may be configured tocorrect, for example, 3 symbol errors per RS block. A final stage in theITU-T J83 Annex B compliant decoder may provide checksum decoding. Thistype of processing provides an accurate way for detecting blockscontaining uncorrectable errors. The ITU-T J.83 Annex A/B/C FEC block214 may be adapted to identify and report uncorrectable errors bysetting a transport error indicator (TEI) flag when the flag is whenenabled in the MPEG-2 stream.

ITU-T J83 Annex A/C compliant decoder support may be provided throughfunction such as frame synchronization, convolutional deinterleaving,Reed-Solomon error correction, and derandomization. A framesynchronization block may be adapted to receive hard decisions from theoutput processing block 270 and lock onto an inverted sync byte pattern.In an aspect of the invention, frame synchronization acquisition andretention characteristics may be set via a host interface.

Once synchronized, a convolutional deinterleaver having programmabledepths may employ a Ramsey Type III approach to deinterleave data. Afterdeinterleaving, resulting data symbols may be transferred to theReed-Solomon decoder which may be adapted to correct, for example, up to8 symbol errors per RS block. The resulting error corrected output maybe derandomized in order to undo the randomization inserted duringtransmitter modulation. A resulting output signal may composite serialor parallel MPEG-2 data with packet sync and a data clock. The AnnexITU-J.83A/C FEC block 214 may report uncorrectable errors by setting atransport error indicator (TEI) flag if the flag is enabled in theMPEG-2 stream.

The NTSC IF demodulator (IFD) block 210 may be adapted to receive andprocess analog NTSC IF television signals and generate an output digitalbaseband composite video broadcasting signal (CVBS) or an output digitalaudio signal which may be either a monaural signal or a BTSC basebandmultiplex signal. FIG. 2 e is a functional block diagram of the NTSC IFdemodulator block 210 of FIG. 2 a in accordance with an embodiment ofthe invention. Referring to FIG. 2 e, the NTSC IF demodulator block 282may comprise a demodulator block 284, an audio data path block 286, anda video data path block 288. The output of the audio data path block 286is an analog multiplexed modulated IF audio output and the output of thevideo data path block 288 is an NTSC output.

The demodulator block 284 is adapted to receive an output signal fromthe inband analog front-end 204, which may be transferred to a digitalmixer in the demodulator block 284. The digital mixer may convert the IFdata in the output signal from the inband analog front-end 204 to acomplex baseband data stream. A pilot recovery loop may be utilized tocontrol operation of the digital mixer. The output of the digital mixermay be filtered and transferred to audio data path block 286.

The audio data path block 286 comprises a complex mixer, afilter-and-decimate stage, and frequency demodulation stage. The complexmixer may translate a FM audio carrier, for example, a 4.5 MHz NTSCcarrier to a baseband signal. The filter-and-decimate stage is adaptedto remove the video from the signal and reduce its sampling rate. Theresulting decimated signal may be frequency demodulated to produce amonaural or a baseband BTSC multiplexed signal.

The video data path block 288 comprises a Nyquist filter, a group delayfilter, an audio trap filter, and a gain/DC-level compensation block.The Nyquist filter may be configured to perform the Nyquist shaping,which is traditionally done by a SAW filter at IF. The group-delayfilter provides group delay compensation within a specified FCC mask.The audio trap filter may remove the audio signal from the video signal.Different audio trap filters may be implemented for different audiocarrier locations. The gain/DC-level compensation block may acquire AGCand DC-level information from a video decoder and adjust the signalaccordingly so as to attain the proper signal loading and DC-level forthe composite video broadcasting signal (CVBS).

The output of the video data path 288 may be routed through a video DAC218 (FIG. 2 a), which is integrated in the single chip integrated DTVreceiver 202 using, for example, high-speed CMOS DAC technology. ThisDAC 218 may be configured to support a composite video broadcastingsignal (CVBS) output. The multiplexed modulated IF audio output from theaudio data path 286 may be adapted to mix the pre-demodulated audiooutput of the NTSC IF demodulator block 210 up to a programmable IF. Theresulting mixed signal may then be routed through a video DAC 220 togenerate an IF audio signal. The DAC 220 may be integrated in the singlechip integrated DTV receiver 202 using, for example, high-speed CMOS DACtechnology. The DAC 220 may also be configured to support a modulated IFaudio output.

The inband output interface block 216, is coupled to the ATSC FEC block212 and the ITU-T J.83 Annex A/B/C FEC block 214 and may be adapted tocleanup signals containing jitter which are received from the ATSC 8/16VSB advanced receiver block 206 and the QAM advanced receiver block 208,which. Accordingly, the inband output interface block 216 may buffer theoutputs from ATSC FEC block 212 and the ITU-T J.83 Annex A/B/C FEC block214 in, for example, a FIFO buffer. Resulting output data may be readout of the FIFO buffer using a smoothed version of the clock which maybe generated by the master PLL block 242. The output clock may befrequency locked with the average of the clock frequencies from the FECs212, 214. The inband output interface block 216 may also be adapted toformat the output of the single chip integrated DTV receiver 202 (FIG. 2a) in a serial or parallel MPEG transport data stream. The band outputinterface block 216 may also perform independent inversion of sync,valid, error and clock, independent suppression of data and/or clock,and/or variable sync and valid duration lengths.

The D/A converter blocks 218 and 220 are integrated into the single chipintegrated DTV receiver 202 using high-speed CMOS DAC technology. TheDAC 218 is configured to support a composite video broadcasting signal(CVBS) output. Accordingly, the DAC 218 may generate a composite NTSCoutput and the DAC 218 is configured to generate an IF audio output.

The BTSC decoder block 222 is coupled to the NTSC IF demodulator block210 and receives input United States BTSC compliant baseband multiplexedTV audio signals from the NTSC IF demodulator block 210. The BTSCdecoder block 222 may be adapted to operate, for example, in a singlechannel mode supporting a plurality of output rates such as 32 KHz, 44.1KHz, and 48 KHz I2S outputs. The BTSC decoder block 222 may also beadapted to produce stereo output, single or dual monaural output, or anindependent separate audio programming (SAP) output.

The BTSC decoder block 222 may be adapted to function as a digitalmulti-channel television sound decoder. A baseband analog BTSC compositesignal extracted by the NTSC IF demodulator block 210 may be received bythe BTSC decoder block 222 and processed fully in digital logic torecover the main left and right channels (L+R), stereo (L/R) channel, orSAP channels. The stereo decoding may include sum (L+R) channel,difference (L−R) channel decoding and rematrixing of sum and differencechannel to retrieve left (L) and right (R) channel. The main channel(sum or mono channel) decoding may be processed as a subset of thestereo decoding. The difference channel decoding may comprise pilot tonerecovery by using, for example, a PLL, double side band (DSB)demodulation, and low pass filtering of the decoded difference signal. Avariable de-emphasis circuit may provide DBX-TV compliant noisereduction. The sum channel decoding may comprise low pass filtering andde-emphasis. A second audio programming (SAP) decoding function maycomprise FM demodulation and DBX variable de-emphasis and an integratedpower detector may be utilized for pilot tone and SAP FM carrier. TheBTSC decoder block 222 may automatically switch between stereo andmonaural modes based on a pilot tone power or SAP decoding. Muting maybe achieved based on a power associated with the SAP FM carrier.

The decoded PCM output from the BTSC decoder block 222 may be programmedto sampling rates of, for example, 32 KHz, 44.1 KHz, and 48 KHz. Thesedata rates may be supported by the on-chip audio DAC 224. Additionally,the left/right channel PCM can be output digitally through either theI²S bus or the on-chip Audio DAC.

The audio DAC block 224 may be adapted to generate and analog signalrepresentative of the Left (L) and/or Right (R) audio informationreceived from the BTSC decoder block 222 or a pre-decoded basebandmultiplexed audio signal from the NTSC IF demodulator block 210. Ananalog output from the DAC block 224, which is representative of thepre-decoded baseband multiplexed audio signal from the NTSC IFdemodulator block 210, may be utilized by an external BTSC decoder whichmay be adapted to receive a baseband input.

The audio DACs may upsample and encode the output of the BTSC decoderblock 222. The analog data output from the audio DACs is a serialpattern corresponding to a digital input into the audio DAC. Thedifferential output may be filtered through an external low-pass filterto generate analog audio. The input to the audio DAC 224 from the BTSCdecoder block 222 may have a sample rate of 48 KHz, 44.1 KHz or 32 KHz.The audio DAC 224 may upsample its input, filter the resulting upsampleddata and modulate the left and right portions of the filtered data.Separate left and right mappers may be utilized to convert the digitalmodulator outputs to serial pulse patterns having different high and lowtimes depending on the modulated value.

FIG. 3 is a block diagram illustrating the out-of-band (OOB) QPSKreceiver for CableCard interface block 226 of FIG. 2 a in accordancewith an embodiment of the invention. For brevity, the out-of-band (OOB)QPSK receiver for CableCard interface block 226 may be referred to as anout-of-band receiver block 226. Referring to FIG. 3, the out-of-bandreceiver block 302 may comprise an out-of-band (OOB) analog front end(AFE) 304, an out-of-band (OOB) QPSK demodulator 306, a DVS-167FEC/DVS-178 FEC block 308 and out-of-band output interface block 310.The OOB AFE block 304 comprises a programmable gain amplifier, an A/Dconverter, a automatic gain control and a voltage controlled oscillator(VCO).

The out-of-band receiver block 302 integrated within the single chipintegrated DTV receiver 202 may be utilized with an IF centered signal.The OOB AFE block 304 integrated within the out-of-band receiver block302 utilizes a frequency agile local oscillator (LO) that may be adaptedto down convert any channel in, for example, the 70-150 MHz frequencyrange to a SAW centered IF. The desired channel may then be sub-sampledby an A/D converter.

The out-of-band QPSK demodulator block 306 may receive an IF sampledinput from the A/D converter and down converts the sampled input tobaseband with a full quadrature mixer driven by a carrier recovery loop.The resulting true-baseband data stream may be resampled under controlof a clock recovery loop to produce a data stream that is correctlysampled in both frequency and phase. The I and Q baseband signalcomponents may then be filtered by dual square-root Nyquist filters.

The out-of-band receiver block 302 may include provisions for, forexample, two automatic gain control loops (AGC). The first loop may beclosed locally at the programmable gain amplifier and may be referred toas the inner IF loop or the AGC loop. The second loop may be closed atthe tuner and may be referred to as the outer tuner loop or thedelayed-AGC loop. Accordingly, gain control may be divided between theinner and outer tuner loops. Each loop comprises a power estimate, athreshold comparison and a first order loop filter. The filter outputmay be utilized to directly control the PGA gain in the case of theinner loop and may be fed into a sigma-delta modulator to generate ananalog control voltage in the case of the outer loop.

A baud recovery loop comprising a timing error discriminant, a loopfilter and a digital timing recovery block may be utilized to control adigital resampler. The timing error discriminant may be adapted tooutput a new value for each baud that is filtered by a digitalintegral-plus-proportional lowpass filter, which features programmablecoefficients. The loop integrator may be read in order to provide loopmonitoring or written for direct control by the acquisition processorblock 240. Data from the loop filter may be applied to a digitallycontrolled frequency synthesizer that may permit the baud rate to bevaried over.

The out-of-band receiver block 302 may comprise out-of-band carrierfrequency/phase recovery and tracking loops, which may be all-digitalloops that are configured to simultaneously offer a wide acquisitionrange and a large phase noise tracking capability. The out-of-bandcarrier frequency/phase recovery and tracking loops may be adapted toestimate the angle and/or direction for frequency/phase compensation. Anintegral plus-proportional filter may be utilized to filter theout-of-band carrier frequency/phase recovery and tracking loops. Thebandwidth of the loop may be adjusted by programming the integrator andlinear coefficients of the integral plus-proportional filter. An outputof the loop filter may be utilized to control, for example, a derotator.The integrator may be read to provide loop monitoring and/or directlywritten to provide control by the acquisition processor 240.

The OOB QPSK modulator block 306 may comprise a decision feedbackequalizer (DFE) with feed-forward taps and feedback taps, which may beadapted to remove or otherwise mitigate the effects of ISI generated byworst-case coaxial cable channels including a wide variety ofimpairments such as un-terminated stubs. The equalizer coefficients maybe updated at, for example, every baud cycle to provide fastconvergence.

The DVS-167 (DAVIC) FEC/DVS-178 (DIGICIPHERII) FEC block 308, which mayalso be referred to as an out-of-band FEC block 308, may comprise aframe synchronization function, a deinterleaving function, aReed-Solomon (RS) decoding function, and a derandomization function. Atleast some of these functions may be programmable so that theout-of-band FEC block 308 may be adapted to handle both the DigiCipherII and DAVIC out-of-band FEC specifications.

The BSC master interface block 228 may comprise a BSC Interface and aSPI interface. The BSC interface may be adapted to support a BSCoperating mode and the SPI interface may be adapted to support a SPIoperating mode. The BSC operating mode allows the single chip integratedDTV receiver 202 (FIG. 2 a) to be controlled over a serial interfacethat, may be compatible with at least a subset of the I²C bus. Amicro-controller interface comprising a serial data (SDA) signal andserial clock (SCL) signal may be utilized to control a plurality ofdevices coupled to a common bus. The addressing of the devices coupledto the common bus may be accomplished through an established protocol onthe two-wire interface. The I²C™ interface specifications define aplurality of addressing modes and protocols that may be utilized formulti-master systems and is hereby incorporated herein by reference. Inone aspect of the invention, the BSC interface 228 may be configured sothat the device coupled to the bus do not respond to a general calladdresses. Notwithstanding, the invention is not so limited.

In general, for I²C devices, both the SDA and SCL signals arebi-directional signals with open-drain output drivers. This allowsmultiple devices to be connected to the bus in a wired AND configurationwith external pull-up resistors. In the single chip integrated DTVreceiver 202, the SDA signal may be bi-directional, but SCL may beutilized as an input since the single chip integrated DTV receiver 202may be adapted to operate as a slave device. In normal operation, datatransfers may be clocked by the SCL signal with one SCL pulse per bit ofdata and the SDA signal may be required to be stable when the SCL signalis high. Transitions of SDA while SCL is high are used to signal theinterface start (S), stop (P), and repeated start (Sr) conditions. Astart condition may be defined as a high-to-low transition of SDA signalwhile the SCL signal is high. A corresponding stop condition may bedefined as a low-to-high transition of SDA signal while the SCL is high.Data transmissions may be preceded by a start condition and endcondition with a stop condition. Repeated starts within a transmissionperiod may be utilized to alter the direction of the data flow, or tochange, for example, a register's base address. Data transmissionoperations may occur in, for example, 8-bit blocks and each block may beacknowledged by a designated receiver through generation of anacknowledge signal (A). The acknowledge signal may be generated on, forexample, a ninth pulse of the SCL signal for each block that istransferred. It should be recognized the signal levels for the operatingmodes which are referenced herein, may be altered without departing fromthe various aspects of the invention.

To perform a write operation, a master device on the common busgenerates a start condition by pulling the SDA signal low while the SCLsignal is high. This signals the single chip integrated DTV receiver tolisten on the common bus for its chip address. The master device on thebus may then send, for example, a chip address and a R/W signal. Eachslave device on the common bus may then compare the address on thecommon bus with its own address and acknowledge the master if there is amatch between the sent address and the devices' own address. If there isno match, the slave device may ignore the rest of a currenttransmission. The slave address for the single chip integrated DTVreceiver 202 (FIG. 2 a) may be programmable via one or more addresspins.

In instances where the master device on the common bus writes to thesingle chip integrated DTV receiver 202, the next byte of data may beinterpreted by the chip as a register base address. This may be utilizedas the address of the location for storing the next byte of datareceived. This base address may be incremented as each byte of data isreceived allowing a contiguous block of registers to be programmed in asingle transmission. Non-contiguous blocks may be programmed utilizingmultiple transmissions or through the use of a repeated start condition,which allows a new chip address and register base address to bespecified without the master device relinquishing bus control. At theend of a transmission, the register base address may point to the lastregister written. The transmission may be terminated with the receipt ofa stop condition.

Read operations may be performed in a somewhat manner similar to a writeoperation. In this regard, the master device on the common bus maygenerate a start condition followed by the chip address and R/W signal.If acknowledged, the master device may listen to the SDA signal whilegenerating the SCL signal. After the master device receives a byte, ifit wants to receive another byte, it will acknowledge the currentlyreceived byte. At the end of a transmission, the master device may notacknowledge the slave and may generate a stop condition to terminate thetransmission. The base address register may be utilized to determine alocation that is being read, and this address may be incremented witheach successive read. At the end of a read operation, the base addressmay point to the register after the last one read. Since the baseaddress register may be programmed through a write operation, a generalread may require two accesses or a single access with a repeatedembedded start in order to change the direction of transmission.

In the SPI operating mode, a pin may be set to logic 1, allowing thesingle chip integrated DTV receiver 202 to be controlled over a serialinterface which may be compatible with at least a subset of thesynchronous serial peripheral interconnect (SPI) bus specification. Amicro-controller interface may be utilized to control a serial clock(SCK) signal, a slave select (SS) signal, a master-in/slave-out (MISO)signal and a master-out/slave-in (MOSI) signal. Support may be added tofacilitate transfers from the single chip integrated DTV receiver 202.Accordingly, the first two bytes sent to the slave device during a SPItransfer as a command byte may be followed by an address byte, and anyremaining bytes may be interpreted as data bytes. The command byte maycomprise a 7-bit reserved word followed by a single bit R/W signal whichdetermines the data direction for the transmission. The next byte may bean 8-bit register base address, which may be utilized as the location tostore the next byte of data received in the case of a write operation orthe next address from which to retrieve data in the case of a readoperation. The base address may be incremented as each byte of data getstransmitted or received and this may allow a contiguous block ofregisters to be stored or read in a single transmission. Non-contiguousblocks may be stored or read through multiple transmissions, which allowa new command byte and register base address to be specified. Thetransmission may be terminated by the de-assertion of the slave selectsignal by the master. The bit assignments are illustrated for exemplarypurposed and the invention is not limited in this regard.

The general-purpose input/output (GPIO)/general-purpose output (GPO)interface block 230 may comprise one or more bits of dedicatedgeneral-purpose I/O logic (GPIO). Each pin may be individuallyprogrammed to be either an input or output via one or more controlregisters. Each pin may be written or read via one or more controlregisters. Each pin may be written to or tri-stated via one or morecontrol register. An ownership register may be provided to determinewhether a host processor or the acquisition processor 240 has writeprivileges to associated data in, data out and/or output enableregisters. The GPIO/GPO pins in the general-purpose input/output(GPIO)/general-purpose output (GPO) interface block 230 may be sharedwith out-of-band and audio outputs.

The EIA/CEA-909 compliant interface block 232 comprises an antennacontrol interface, which is adapted to facilitate optimal televisionreception. The single chip integrated DTV receiver allows a host systemto control the characteristics and/or position of an antenna apparatusin order to optimize reception of a signal by the antenna apparatus. TheEIA/CEA-909 compliant interface block 232 has the capability to handlemode A and/or mode B operation. A state machine within the interfacedetermines whether the connected antenna is capable of Mode B operation.

In one embodiment of the invention, the EIA/CEA-909 compliant interfaceblock 232 comprises an antenna detect input pin, a receive data inputpin and a transmit data output pin. The antenna detect pin may enable ordisable the EIA/CEA-909 compliant interface block 232 whenever anantenna is connected or removed. The receive data input pin may beconfigured so that it is valid for mode B operation. The receive data isexternally buffered data from the antenna. The transmit data pin may beutilized to transfer data from the single chip integrated DTV receiverto an antenna coupled thereto. The receive and transmit data may bepulse width modulated at a bit rate of about 8 KHz. In an embodiment ofthe invention, logic ‘0’ may be approximately defined by a 41 μsecpulse, while logic ‘1’ may be approximately defined by an 83 μsec pulse.However, the invention is not limited to these exemplary values.

FIG. 4 is a flow chart illustrating exemplary steps that may be utilizedby a master state machine for the EIA/CEA-909 compliant interface block232 in accordance with an embodiment of the invention. Referring to FIG.4, in step 502, initialization of the EIA/CEA-909 compliant interface232 occurs, followed in step 504 by an idle state. In step 506, adetermination is made whether the antenna detect signal (ant_det) isasserted. If the antenna detect signal (ant_det) is not asserted, thenstep 506 is repeated. If the antenna detect signal (ant_det) isasserted, then in step 508, a transmit state machine may be enabled. Instep 510, a determination is made whether transmission is done. Iftransmission is not done, then step 510 is repeated. If transmission isdone, then in step 512, a determination is made whether there was aninitial transmission or a mode B operation. If there was an initialtransmission, then in step 514, a message-to-message timer may beenabled. In step 516, a determination is made whether the timer hasexpired. If the timer has not expired, then step 516 is repeated. If thetimer has expired, then in step 516, the next message is awaited. Instep 520, a determination is made whether the new message is received.If a new message is not received, then control passes back to step 518.If a new message is received, then control passes back to step 508,where the transmit state machine is enabled. In step 512, if it isdetermined that it was not an initial transmission or mode B operation,then in step 522, a receive state machine is enabled. In step 524, adetermination is made whether receiving is done. If receiving is notdone, the step 524 is repeated. If receiving is done, then step 518executed, where the next message is awaited.

The debug interface block 234 may be, for example, a JTAG compliantdebug interface. The debug interface block 234 may be a test access port(TAP) that is compatible with IEEE Std. 1149.1, commonly known as theJTAG boundary scan interface.

The BSC/SPI slave interface block 236 may comprise a BSC interface blockand an SPI interface block. The BSC interface block may be adapted tocontrol a BSC interface mode and the serial peripheral interconnect(SPI) interface block may be adapted to control an SPI interface mode.In the BSC mode, the single chip integrated DTV receiver 202 may becontrolled over a serial interface that may be compatible with, forexample, at least a subset of the I²C bus. In an embodiment of theinvention, two (2) signals comprising a serial data (SDA) signal and aserial clock (SCL) signal may be utilized to control a plurality ofdevices coupled to a common serial bus. In general, the devices coupledto a serial bus may be addressed through various protocols establishedfor providing communication over the two-wire interface. For example,the I²C specification defines a plurality of addressing modes and/orprotocols for use in a two (2) wired serial bus application. Althoughthe BSC interface block may utilize a subset of the I²C serial businterface, the serial bus may be adapted so that devices coupled to theserial bus do not respond to general call addresses.

In SPI mode, the single chip integrated DTV receiver 202 may becontrolled via a serial interface which may be compatible with at leasta subset of the synchronous serial peripheral interconnect (SPI) bus. Inone embodiment of the invention, four (4) signals comprising a serialclock (SCK) signal, a slave select (SS) signal, a master-in/slave-out(MISO) signal and a master-out/slave-in (MOSI) signal may be utilized tocontrol a plurality of devices coupled to a common serial bus. At leastone protocol layer of the SPI interface may be enhanced or at least onelayer may be added in order to facilitate transfers from the single chipintegrated DTV receiver 202.

The acquisition processor block 240 may comprise at least oneprogrammable acquisition processor. The acquisition processor operationsmay be managed and/or controlled by suitable code so the host programrequirements may be minimized. A simple application programminginterface (API) may be utilized to communicate from the host to theinternal processor.

The host access buffer (HAB) block 238 may be utilized by the host toissue commands to the single chip integrated DTV receiver 202, andrequest the single chip integrated DTV receiver's status and acquisitionprocessor's internal state. To access the on-chip receivers in theintegrated in the single chip integrated DTV receiver 202, the host may,for example, post a read or write request in the HAB 238 to access theregisters. When the acquisition processor 240 is in a state where it canservice host requests, the acquisition processor 240 may perform therequest, then returns to its other programming tasks. This allows arequest to be serviced in a time slot when it is convenient for theacquisition processor 240 to do so without affecting acquisition timing.

The host access buffer 238 is adapted to accommodate a series of accessrequests. Each request may contain information about the location thatis to be accessed, identify a read or write operation, and define anaccess length, a required number of data fields, and a status bitassociated with the request. Arbitration for providing access to thehost access buffer 238 may be handled at the hardware level and/or thesoftware level. A host access buffer command bit (HAB_CMD) bit may beutilized to prohibit simultaneous access from a host processor and alocal processor. The host may setup the access, and the acquisitionprocessor (AP) 240 may be prohibited from accessing the host accessbuffer 238 when the HAB_CMD bit is asserted. After a request has beenissued, the host may deassert the HAB_CMD, and the acquisition processor240 may be allowed access. The host may not access the host accessbuffer 238 until the acquisition processor asserts the HAB_CMD bit. Oneor more bits may be utilized to control access to the host access bufferfrom a host or local processor.

When a host processor determines that it needs to access the single chipintegrated DTV receiver, it may check the status of the HAB_CMD bit tomake sure there are no pending requests that have not been serviced. Ininstances where the host processor attempt to perform an access to theHAB 238 while the HAB_CMD=1, a HAB access violation may occur. In thisinstance, the host interface may continue to complete the access but theHAB 238 may not actually be written in case of a write, or the data thatis read from the HAB 238 may not be valid in case of a read.Accordingly, an error condition may be generated and/or reported to for,example, a host system and/or processor. For example, a HAB error bit(H_HAB_ER) may be set in a status register such as a HAB status register(H_STAT1) and can generate an interrupt to the host processor or systemdepending on the value of the interrupt enable. This type of violationmay have no affect on the operation of the acquisition processor whichcontinues without exception. If the HAB_CMD=0, the host may post arequest, or a series of requests up to the point where the requests mayoccupy the available space in the HAB 238. After the requests areposted, the host processor may set the HAB_CMD bit to logic 1. In anaspect of the invention, an interrupt may be generated to theacquisition processor 240 and/or host processor when the HAB_CMD bit isset to logic 1. Once the HAB 238 command bit is set to logic 1, the hostprocessor may not be able to access the HAB 238 until the entire bufferhas been serviced and HAB_CMD is cleared. The host processor or systemmay be dependent on the acquisition processor's ability to perform therequests in a timely manner.

In instances where a read is posted in the HAB 238, the host processormay need to wait until the HAB_CMD bit is cleared by the acquisitionprocessor 240. This may indicate that the host access buffer 238contains all the requested data. The host may then perform reads on thehost access buffer 238 and fetch the requested data. Once the data isretrieved, the host may be adapted to post more requests as required.

The host access block 238 may be configured to queue a series of accessrequests. Each request may contain information corresponding to thelocation(s) to be accessed, a read/write indicator, an access length,the required number of data fields, and a status bit for the request.Arbitration for HAB access may be managed at the hardware level. TheHAB_CMD bit may be utilized to prohibit access from the host and theacquisition processor simultaneously and the host may be adapted toconfigure the access. The acquisition processor block 240 may beprohibited from host access block 238 access, when the HAB_CMD bit islogic 0. After requests have been issued, the host may set the HAB_CMDbit to logic 1, and the acquisition processor may be allowed access,while the host may not be permitted to further access the host accessbuffer 238 until the acquisition processor 240 clears the HAB_CMD bit.It should be recognized that the logic levels may be altered for hostaccess block 238 operations without departing from the various aspectsof the invention.

FIG. 5 a is a flow chart illustrating exemplary steps that may beutilized for accessing the HAB by a host processor in accordance with anembodiment of the invention. Referring to FIG. 5 a, in step 502, adetermination is made as to whether access is needed to the host accessbuffer. If no access to the host access buffer is needed, then step 502may continue looping until access is needed. If no access to the hostbuffer is needed, then control returns to step 502. If access to thehost access buffer is needed, then in step 504, a determination is madeas to whether the HAB_CMD bit is equal to logic 0. In step 506, some orall requests may be posted to the host access buffer. After the requestsare posted, in step 508, the HAB_CMD bit may be set to logic 1. In step510, a determination is made as to whether there are any readoperations. If there are no read operations, then control returns tostep 502. However, if there are read operations, then in step 512, itmay be determined whether the HAB_CMD bit is equal to logic 0. If theHAB_CMD bit is not equal to logic 0, then step 512 is repeated until theHAB_CMD bit is equal to logic 0. When it is determined that the HAB_CMDbit is equal to logic 0, then in step 514, the host access buffer may beread. Subsequently, control may pass back to step 502.

When the acquisition processor 240 is capable of servicing a requestfrom the host processor, the acquisition processor 240 may execute, forexample, a host access buffer service routine. The acquisition processormay be adapted to initialize or otherwise setup an interrupt timer tothe period allowed for performing accesses. In this regard, accesses maycontinue until a timer interrupt is generated. The acquisition processor240 may determine whether the HAB_CMD bit is set. If so, then theacquisition processor 240 may initiate the requested series of accessesby scanning the host access buffer 238 looking for the first requestthat has not yet been serviced. This may be achieved by checking thelocal status bit that that may be associated with each request. Once theacquisition processor 240 finds a request that has not been serviced,that request may be serviced by the acquisition processor 240. Whenprocessing of that request is complete, the acquisition processor 240may set the request status and moves to the next request. In instanceswhen there are no more request in the host access buffer, theacquisition processor 238 may clear the HAB_CMD bit and may subsequentlyreturn to check for other requests in the host access buffer.

FIG. 5 b is a flow chart illustrating exemplary steps that may beutilized for accessing and processing requests in the HAB 238 by anacquisition processor in accordance with an embodiment of the invention.Referring to FIG. 5 b, in step 520, the acquisition processor is readyto provide service to the host processor. In step 504, in step 522, atimer may be started. In step 524, it may be determined whether theHAB_CMD bit is equal to logic 1. If the HAB_CMD is not set to 1, thenstep 524 may be repeated until the HAB_CMD bit is equal to logic 1. Ifthe HAB_CMD bit is equal to logic 1, then in step 526, the acquisitionprocessor may look for unserviced requests in the host access buffer.The unserviced requests may then be serviced in step 528. In step 530, arequest status associated with each of the serviced requests may be set.In step 532, it may be determined whether there are more requests to beserviced. If there are no more requests to be serviced, then controlreturns to step 526. However, if there are more requests to beprocessed, then in step 534, the HAB_CMD bit may be set to logic zero orcleared. Control may then pass back to step 524.

Although the invention is sometimes described in term of functionalblocks, some of the functions handled by a particular block of thesingle chip integrated DTV receiver 202 (FIG. 2 a) may not be limited tothe manner in which they are described. Accordingly, a function for aparticular block may be accomplished in one or more of the other blocksintegrated within the single chip integrated DTV receiver 202. Forexample, some of the functions of the inband output interface block 216may be integrated in the ITU-T J.83 A/B/C FEC block 214. In anotherexample, some of the functions of the inband output interface block 216may be integrated in the ATSC FEC block 212.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method for processing signals in a communication system, the methodcomprising: demodulating a wirelessly received digital inband signal anda wirelessly received digital out-of-band signal via a digitaltelevision (DTV) receiver, wherein said demodulating comprisesadaptively equalizing said received digital inband signal and saidreceived digital out-of-band signal; error correcting said demodulateddigital inband signal and said demodulated digital out-of-band signal;and generating one or more TV channels based on said demodulation anderror correction of said wirelessly received digital inband signal andsaid wirelessly received digital out-of-band signal.
 2. The methodaccording to claim 1, wherein said wirelessly received digital inbandsignal comprises one or more of a VSB signal, a NTSC signal and/or a QAMsignal.
 3. The method according to claim 1, comprising decoding saidwirelessly received digital inband signal.
 4. The method according toclaim 3, comprising generating an audio output based on said decoding ofsaid wirelessly received digital inband signal.
 5. The method accordingto claim 4, wherein said audio output comprises one or more of an I2Saudio, stereo audio, monaural audio, and/or multiplexed baseband audio.6. The method according to claim 1, comprising generating an MPEGtransport stream from said demodulated wirelessly received digitalinband signal.
 7. The method according to claim 6, wherein saidgenerated MPEG transport stream comprises a serial MPEG transportstream.
 8. The method according to claim 6, wherein said generated MPEGtransport stream comprises a parallel MPEG transport stream.
 9. Themethod according to claim 1, comprising generating a composite NTSCsignal from said demodulated wirelessly received digital inband signal.10. The method according to claim 1, comprising demodulating saidwirelessly received digital out-of-band signal utilizing a QPSKdemodulator.
 11. The method according to claim 1, comprising generatingan output out-of-band transport stream from said wirelessly receiveddigital out-of-band signal.
 12. The method according to claim 11,wherein said out-of-band transport stream comprises CableCard encryptionand security data.
 13. A non-transitory machine-readable storage havingstored thereon, a computer program having at least one code section forprocessing signals in a communication system, the at least one codesection being executable by a machine for causing the machine to performsteps comprising: demodulating a wirelessly received digital inbandsignal and a wirelessly received digital out-of-band signal via adigital television (DTV) receiver, wherein said demodulating comprisesadaptively equalizing said received digital inband signal and saidreceived digital out-of-band signal; error correcting said demodulateddigital inband signal and said demodulated digital out-of-band signal;and generating one or more TV channels based on said demodulation anderror correction of said wirelessly received digital inband signal andsaid wirelessly received digital out-of-band signal.
 14. Themachine-readable storage according to claim 13, wherein said wirelesslyreceived digital inband signal comprises one or more of a VSB signal, aNTSC signal and/or a QAM signal.
 15. The machine-readable storageaccording to claim 13, comprising code for decoding said wirelesslyreceived digital inband signal.
 16. The machine-readable storageaccording to claim 15, comprising code for generating an audio outputbased on said decoding of said wirelessly received digital inbandsignal.
 17. The machine-readable storage according to claim 16, whereinsaid audio output comprises one or more of an I2S audio, stereo audio,monaural audio, and/or multiplexed baseband audio.
 18. Themachine-readable storage according to claim 13, comprising code forgenerating an MPEG transport stream from said demodulated wirelesslyreceived digital inband signal.
 19. The machine-readable storageaccording to claim 18, wherein said generated MPEG transport streamcomprises a serial MPEG transport stream.
 20. The machine-readablestorage according to claim 18, wherein said generated MPEG transportstream comprises a parallel MPEG transport stream.
 21. Themachine-readable storage according to claim 13, comprising code forgenerating a composite NTSC signal from said demodulated wirelesslyreceived digital inband signal.
 22. The machine-readable storageaccording to claim 13, comprising code for demodulating said wirelesslyreceived digital out-of-band signal utilizing a QPSK demodulator. 23.The machine-readable storage according to claim 13, comprising code forgenerating an output out-of-band transport stream from said wirelesslyreceived digital out-of-band signal.
 24. The machine-readable storageaccording to claim 23, wherein said out-of-band transport streamcomprises CableCard encryption and security data.
 25. A system forprocessing signals in a communication system, the system comprising: oneor more circuits that enables demodulating a wirelessly received digitalinband signal and a wirelessly received digital out-of-band signal via adigital televition (DTV) receiver, wherein said demodulating comprisesadaptively equalizing said received digital inband signal and saidreceived digital out-of-band signal; said one or more circuits enableserror correcting said demodulated digital inband signal and saiddemodulated digital out-of-band signal; and said one or more circuitsenables generating one or more TV channels based on said demodulationand error correction of said wirelessly received digital inband signaland said wirelessly received digital out-of-band signal.
 26. The systemaccording to claim 25, wherein said wirelessly received digital inbandsignal comprises one or more of a VSB signal, a NTSC signal and/or a QAMsignal.
 27. The system according to claim 25, wherein said one or morecircuits enables decoding said wirelessly received digital inbandsignal.
 28. The system according to claim 27, wherein said one or morecircuits enables generating an audio output based on said decoding ofsaid wirelessly received digital inband signal.
 29. The system accordingto claim 28, wherein said audio output comprises one or more of an I2Saudio, stereo audio, monaural audio, and/or multiplexed baseband audio.30. The system according to claim 25, wherein said one or more circuitsenables generating an MPEG transport stream from said demodulatedwirelessly received digital inband signal.
 31. The system according toclaim 30, wherein said generated MPEG transport stream comprises aserial MPEG transport stream.
 32. The system according to claim 30,wherein said generated MPEG transport stream comprises a parallel MPEGtransport stream.
 33. The system according to claim 25, wherein said oneor more circuits enables generating a composite NTSC signal from saiddemodulated wirelessly received digital inband signal.
 34. The systemaccording to claim 25, wherein said one or more circuits enablesdemodulating said wirelessly received digital out-of-band signalutilizing a QPSK demodulator.
 35. The system according to claim 25,wherein said one or more circuits enables generating an outputout-of-band transport stream from said wirelessly received digitalout-of-band signal.
 36. The system according to claim 35, wherein saidout-of-band transport stream comprises CableCard encryption and securitydata.